/*
 * Copyright (c) 1996, 1999, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
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 *
 *
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 *
 *
 *
 *
 */

package java.util.zip;

import java.io.FilterOutputStream;
import java.io.OutputStream;
import java.io.IOException;

/**
 * An output stream that also maintains a checksum of the data being
 * written. The checksum can then be used to verify the integrity of
 * the output data.
 *
 * @author David Connelly
 * @see Checksum
 */
public class CheckedOutputStream extends FilterOutputStream {

  private Checksum cksum;

  /**
   * Creates an output stream with the specified Checksum.
   *
   * @param out the output stream
   * @param cksum the checksum
   */
  public CheckedOutputStream(OutputStream out, Checksum cksum) {
    super(out);
    this.cksum = cksum;
  }

  /**
   * Writes a byte. Will block until the byte is actually written.
   *
   * @param b the byte to be written
   * @throws IOException if an I/O error has occurred
   */
  public void write(int b) throws IOException {
    out.write(b);
    cksum.update(b);
  }

  /**
   * Writes an array of bytes. Will block until the bytes are
   * actually written.
   *
   * @param b the data to be written
   * @param off the start offset of the data
   * @param len the number of bytes to be written
   * @throws IOException if an I/O error has occurred
   */
  public void write(byte[] b, int off, int len) throws IOException {
    out.write(b, off, len);
    cksum.update(b, off, len);
  }

  /**
   * Returns the Checksum for this output stream.
   *
   * @return the Checksum
   */
  public Checksum getChecksum() {
    return cksum;
  }
}
